Digital holography microscope (DHM), and inspection method and semiconductor manufacturing method using the DHM

ABSTRACT

A low-cost digital holography microscope (DHM) that is capable of performing inspection at high speed while accurately inspecting an inspection object at high resolution, an inspection method using the DHM, and a method of manufacturing a semiconductor device by using the DHM are provided. The DHM includes: a light source configured to generate and output light; a beam splitter configured to cause the light to be incident on an inspection object and output reflected light from the inspection object; and a detector configured to detect the reflected light, wherein, when the reflected light includes interference light, the detector generates a hologram of the interference light, and wherein no lens is present in a path from the light source to the detector.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2018-0064484, filed on Jun. 4, 2018, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

The inventive concept relates to an inspection apparatus and aninspection method, and more particularly, to an inspection apparatus andan inspection method for accurately checking the presence or absence ofdefects on an object to be inspected.

An electron microscope, ellipsometry, or the like has been used to checkthe presence or absence of defects on an object to be inspected, forexample, a wafer. Among them, the electron microscope is an apparatuswhich makes an enlarged image of an object by using an electron beam andan electron lens. The electron microscope may overcome the resolutionlimit of conventional optical microscopes and may perform microscopicobservation, and thus is widely used for wafer inspection. Ellipsometrymay calculate information about a sample by analyzing a polarizationchange of reflected light reflected from the sample (e.g., a wafersurface). For example, when light is reflected from a sample, thepolarization state of reflected light changes depending on opticalproperties of a sample material and the thickness of a sample layer.Ellipsometry may derive physical information about the sample bymeasuring such polarization changes.

SUMMARY

The inventive concept provides a low-cost digital holography microscope(DHM) that is capable of performing inspection at high speed whileaccurately inspecting an object at high resolution, an inspection methodusing the DHM, and a method of manufacturing a semiconductor device byusing the DHM.

According to an aspect of the inventive concept, there is provided adigital holography microscope (DHM) including: a light source configuredto generate and output light; a beam splitter configured to cause thelight to be incident on an inspection object and output reflected lightfrom the inspection object; and a detector configured to detect thereflected light, wherein the detector generates a hologram when thereflected light includes interference light, and wherein the DHM has alens-free path from the light source to the detector.

According to another aspect of the inventive concept, there is provideda digital holography microscope (DHM) including: a light sourceconfigured to generate and output light; a detector configured to detectreflected light produced when the light is vertically incident on anupper surface of an inspection object or incident at a set inclinationangle; and an analysis and determination unit configured to analyze thereflected light to determine whether a defect is present in theinspection object, wherein the detector generates a hologram when thereflected light includes interference light and the analysis anddetermination unit analyzes the hologram, and wherein the DHM has alens-free path from the light source to the detector.

According to another aspect of the inventive concept, there is providedan inspection method using a digital holography microscope (DHM)comprising a light source and a detector, the inspection methodincluding: generating light and making the light incident on aninspection object; detecting reflected light from the inspection object;analyzing the reflected light to determine whether a defect is presentin the inspection object; and generating a hologram and analyzing thehologram when the reflected light includes interference light, whereinthe DHM has a lens-free path from the light source to the detector.

According to another aspect of the inventive concept, there is provideda method of manufacturing a semiconductor device by using a digitalholography microscope (DHM) comprising a light source and a detector,the method including: generating light and making the light incident onan inspection object; detecting reflected light from the inspectionobject; analyzing the reflected light to determine whether a defect ispresent in the inspection object; generating a hologram and analyzingthe hologram when the reflected light includes interference light; andperforming a semiconductor process on the inspection object when nodefect is present in the inspection object, wherein the DHM has alens-free path from the light source to the detector.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIG. 1A is a block diagram of a digital holography microscope (DHM)according to an embodiment of the inventive concept, and FIG. 1B is aconceptual diagram of the DHM of FIG. 1A;

FIG. 2A is a block diagram of a DHM according to an embodiment of theinventive concept, and FIGS. 2B to 2D are conceptual diagrams of the DHMof FIG. 2A;

FIGS. 3A and 3B are conceptual diagrams of a DHM according to anembodiment of the inventive concept;

FIGS. 4 to 8 are conceptual diagrams of DHMs according to embodiments ofthe inventive concept;

FIG. 9A is a block diagram of a DHM according to an embodiment of theinventive concept, and FIG. 9B is a conceptual diagram of the DHM ofFIG. 9A;

FIGS. 10 to 13 are conceptual diagrams of DHMs according to embodimentsof the inventive concept;

FIG. 14 is a flowchart of an inspection method using a DHM according toan embodiment of the inventive concept;

FIGS. 15A to 15D are flowcharts illustrating in more detail variousembodiments of an operation of making light incident on an inspectionobject, in the inspection method of FIG. 14; and

FIG. 16 is a flowchart of a method of manufacturing a semiconductordevice by using a DHM, according to an embodiment of the inventiveconcept.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the inventive concept will be described indetail with reference to the accompanying drawings. Like referencenumerals denote like elements in the drawings, and redundant descriptionthereof will be omitted.

FIG. 1A is a block diagram of a digital holography microscope (DHM) 100according to an embodiment of the inventive concept, and FIG. 1B is aconceptual diagram of the DHM 100 according to embodiments of theinventive concept.

Referring to FIGS. 1A and 1B, the DHM 100 according to embodiments ofthe inventive concept may include a light source 110, a beam splitter120, a detector 130, a reconstruction unit 140, and an analysis anddetermination unit 150.

The light source 110 may be a coherent light source that generates andoutputs coherent light. Coherent light may refer to light that causesinterference, such as constructive interference or destructiveinterference. The constructive interference indicates that two or morelights are strongly merged together when the two or more lights overlapeach other, and the destructive interference indicates that two or morelights are weakly merged together when the two or more lights overlapeach other. For example, the light source 110 may be a non-continuousspectral light source, such as a sodium lamp, a mercury lamp, or thelike, and may be a mono-chromatic point source. In the DHM 100 accordingto one embodiment, the light source 110 may be, for example, a laserthat generates and outputs laser light. The laser light is monochromaticlight with high coherence spatially and temporally, and examples of thelaser include a gas laser such as He—Ne and CO2, a solid laser such asruby and YAG, and a semiconductor laser such as GaAs and InP.

The beam splitter 120 may make light from the light source 110 incidenton an object 200 to be inspected (hereinafter, referred to as aninspection object 200) and may output reflected light reflected from theinspection object 200 toward the detector 130. The inspection object 200may be positioned on a stage 160. The inspection object 200 may be, forexample, a wafer including a plurality of semiconductor devices.However, the inspection object 200 is not limited to a wafer. Forexample, the inspection object 200 may be a display glass substrate. Thebeam splitter 120 may transmit or reflect light incident from the lightsource 110 and make the light incident on the inspection object 200 andmay reflect or transmit reflected light from the inspection object 200and output the reflected light toward the detector 130.

Light incident through the beam splitter 120 may be reflected by theinspection object 200. When there is a defect De in the inspectionobject 200, the light may be diffracted and reflected at a portion ofthe inspection object 200 where there is the defect De, due to thedefect De. In a portion of the inspection object 200 where no defect Deis present, the light may be reflected as it is without diffraction. InFIG. 1B, light diffracted and reflected at the portion where there isthe defect De is indicated by a dotted arrow, and light reflectedwithout diffraction is indicated by a solid arrow. Hereinafter, lightdiffracted and reflected due to the defect De is referred to as a firstreflected light R1, and light reflected without diffraction is referredto as a second reflected light R2.

Light incident on the portion where there is the defect De may bediffracted by the defect De, and the diffracted light may be reflectedfrom the inspection object 200. In addition, light reflected from theinspection object 200 may also be diffracted by the defect De. Thus, thediffraction may include both diffraction of incident light by the defectDe and diffraction of reflected light by the defect De. The defect Demay be fine particles on the inspection object 200, scratches formed onthe inspection object 200, or the like. However, the defect De is notlimited to fine particles or scratches. Generally, the defect De doesnot denote all particles or scratches but particles or scratches havingsizes out of tolerance, and the same concept may be used below. Thedefect De may cause defects in the inspection object 200 in a laterprocess for the inspection object. For example, when the inspectionobject 200 is a wafer, in a later semiconductor process for the wafer,the defect De may cause defects in semiconductor devices in the wafer.Accordingly, it is possible to prevent defects in the inspection object200 or omit an unnecessary process for the inspection object bydetecting the defect De in the inspection object 200 in advance throughinspection and then removing the defect De or discarding the inspectionobject 200 itself.

The first reflected light R1 and the second reflected light R2 mayoverlap each other in the beam splitter 120 to cause interference. Lightcaused by the interference, that is, interference light may be incidenton the detector 130 from the beam splitter 120. When no defect De ispresent in the inspection object 200, the first reflected light R1 maynot be present and only the second reflected light R2 may be present.Accordingly, only the second reflected light R2 may be incident on thedetector 130 through the beam splitter 120 and interference may notoccur.

The detector 130 may generate a hologram for the interference lightincident from the beam splitter 120. The hologram may include, forexample, the intensity of the interference light and phase informationon the interference light. The detector 130 may be implemented by, forexample, a charge coupled device (CCD) camera or a CMOS image sensor(CIS) camera. When only the second reflected light R2 is incident on thedetector 130 because no defect De is present in the inspection object200, the detector 130 may not generate a hologram.

In general, the hologram may denote a photograph of a three-dimensionalimage which is stereoscopically viewed like the real thing. The hologrammay be made using the principle of holography. The general principle ofholography is as follows. Light emitted from a laser is split into two,one light is directly irradiated onto a screen, and the other light isreflected from an object to be viewed and reflected light is irradiatedonto the screen. In this case, the light directly irradiated onto thescreen is referred to as a reference beam, and the light reflected fromthe object is referred to as an object beam. Since the object beam islight reflected from the surface of the object, the phase of the objectbeam varies depending on each position on the surface of the object.Accordingly, the reference beam and the object beam may interfere witheach other and an interference fringe may be formed on the screen. Afilm in which such interference fringes are stored is called a hologram.Typical photographs store only light intensity, but holograms may storelight intensity and phase information.

The reconstruction unit 140 may digitally reconstruct a hologram fromthe detector 130 to generate an image of the inspection object 200. InFIG. 1B, a hologram Hg(λ) generated by the detector 130 is shown on theright side of the detector 130, and an image Im of the inspection object200 generated by the reconstruction unit 140 based on the hologram Hg(λ)is shown on the right side of the hologram Hg. The intensity and phaseof light in an interference fringe may vary depending on the wavelengthλ of light used for generating a hologram, and thus the shape of theinterference fringe may also be changed. Thus, in general, thewavelength λ of light used in the hologram may be described together inthe hologram.

An operation of generating the image Im of the inspection object 200 bythe reconstruction unit 140 may be automatically performed through areconstruction program. For example, when information on a hologram fromthe detector 130 is input to the reconstruction unit 140, the image Imof the inspection object 200 may be automatically generated through areconstruction program in the reconstruction unit 140. Thereconstruction unit 140 may be implemented by a general personalcomputer (PC), a workstation, a super computer, or the like forexecuting a reconstruction program.

When the detector 130 does not generate a hologram, for example, when nodefect De is present in the inspection object 200 and thus interferencelight is not generated and only the second reflected light R2 isincident on the detector 130 and thus the detector 130 does not generatea hologram, the reconstruction unit 140 may not generate an image of theinspection object 200. According to an embodiment of the inventiveconcept, the reconstruction unit 140 may generate an image of the secondreflected light R2 of the detector 130 as an image of the inspectionobject 200.

The analysis and determination unit 150 analyzes reflected light and/ora hologram of the detector 130 or an image of the reconstruction unit140 to determine whether there is a defect in the inspection object 200.That is, when there is a defect De in the inspection object 200, theanalysis and determination unit 150 may determine that the inspectionobject 200 is abnormal. When no defect is present in the inspectionobject 200, the analysis and determination unit 150 may determine thatthe inspection object 200 is normal. The analysis and determination unit150 may be implemented by, for example, a general PC, a workstation, asuper computer, or the like for executing an analysis and determinationprogram. According to an embodiment of the inventive concept, theanalysis and determination unit 150 may be included in one computerdevice together with the reconstruction unit 140. According to anembodiment of the inventive concept, the detector 130 may also beincluded in a computer device together with the reconstruction unit 140and/or the analysis and determination unit 150.

According to an embodiment of the inventive concept, the DHM may notinclude the reconstruction unit 140. In such a case, the analysis anddetermination unit 150 may analyze a hologram of the detector 130 todetermine whether there is a defect in the inspection object 200. Inaddition, the analysis and determination unit 150 may analyze reflectedlight of the detector 130 to determine whether there is a defect in theinspection object 200. As described above, when no defect is present inthe inspection object 200, the detector 130 may not generate a hologram.Thus, the reconstruction unit 140 may not generate an image of theinspection object 200, or may generate an image of the reflected lightof the detector 130 as an image of the inspection object 200. When thereconstruction unit 140 does not generate an image of the inspectionobject 200, the analysis and determination unit 150 may analyze an imageof the reflected light of the detector 130 to determine whether there isa defect in the inspection object 200.

In the DHM 100 according to one embodiment, there may be no lens in apath of light between the light source 110 and the detector 130. Forexample, the DHM 100 according to embodiments of the inventive conceptmay be a lens-free DHM. Accordingly, the DHM 100 according toembodiments of the inventive concept may solve all the problems that mayoccur in existing DHMs, and may also inspect the inspection object 200at high speed.

More specifically, in the existing DHM, inspection is performed based ona method of generating a general hologram. That is, the existing DHMdivides light output from a light source into two lights on two paths,light corresponding to the object beam is directed to a camera afterpassing through an inspection object or being reflected from theinspection object, and light corresponding to the reference beam isdirected to the camera through another path. Thus, the existing DHMinspects the inspection object by detecting an interference phenomenonbetween the two lights, that is, the light corresponding to the objectbeam and the light corresponding to the reference beam, andreconstructing images from the interference phenomenon. The existing DHMmay have some problems due to an optical system configuration thereof.For example, the light on each of the paths has to be accurately alignedfor accurate interference formation, but the accurate alignment of thelight is not easy due to the mechanical configuration of the existingDHM. Also, since a lens system is used, there is a trade offrelationship between the resolution of the lens system and the field ofview (FOV) thereof. That is, when the resolution increases, the FOVnarrows and inspection speed slows down. When the resolution decreases,the FOV widens but inspection accuracy is lowered. Furthermore, theaccuracy of image reconstruction may be reduced due to multiplereflections of each part, in accordance with the use of an opticalsystem including a lens. In particular, in the case of a DHM using ahigh-resolution optical system, the FOV is so small that inspection timebecomes very long. Thus, the DHM using a high-resolution optical systemmay not be used for inspection objects requiring high speed fullinspection.

On the other hand, in the DHM 100 according to some embodiments, thepath of the first reflected light R1 corresponding to the object beamand the path of the second reflected light R2 corresponding to thereference beam may be substantially the same. Thus, a separate opticalsystem other than the beam splitter 120 may be unnecessary. Thus, theproblem of aligning light of existing DHMs, a trade-off problem betweenresolution and FOV according to a lens system, and a reflection problemof each part of an optical system may be solved. In addition, since theDHM 100 according to embodiments of the inventive concept does not havea lens, the FOV is very wide and thus the inspection object 200 may beinspected at high speed.

FIG. 2A is a block diagram of a DHM 100 a according to an embodiment ofthe inventive concept, and FIGS. 2B to 2D are conceptual diagrams of theDHM 100 a according to embodiments of the inventive concept.Descriptions already given with reference to FIGS. 1A and 1B will bebriefly described or omitted.

Referring to FIGS. 2A to 2D, the DHM 100 a according to embodiments ofthe inventive concept may be different from the DHM 100 of FIG. 1A inthat a light source 110 a is a multi-wavelength light source and thereis a spectrometer 115 between the light source 110 a and a beam splitter120.

In the DHM 100 a according to embodiments of the inventive concept, thelight source 110 a may be a multi-wavelength light source that generatesand outputs multi-wavelength light. For example, the light source 110 amay generate and output light in a visible light and/or ultravioletlight band. The wavelength band of the multi-wavelength light generatedby the light source 110 a is not limited to the above range.

The spectrometer 115 may separate multi-wavelength light from the lightsource 110 a by wavelengths. The spectrometer 115 may be implemented,for example, through a prism or through a diffraction grating. FIG. 2Billustrates a spectrometer 115 implemented through a prism. A slit plate117 is positioned at the front of the prism, and light having a requiredwavelength may be output through a slit or pin-hole formed in the slitplate 117. In addition, by moving the slit plate 117, light having aplurality of wavelengths may be output.

Depending on the wavelength of light, the shape of light (i.e., firstreflected light R1) diffracted and reflected at a portion where there isa defect De of an inspection object 200 may be changed. FIG. 2C shows anexample in which the shape of the first reflected light R1 variesdepending on a first wavelength λ1, a second wavelength λ2, and a thirdwavelength λ3, which are different from each other. Also, as the shapeof the first reflected light R1 varies depending on the wavelength oflight, intensity and phase information in a hologram and the shape ofthe hologram may vary. FIG. 2D shows an example in which the shape of agenerated hologram varies depending on the first wavelength λ1, thesecond wavelength λ2, and the third wavelength λ3.

In the DHM 100 a according to embodiments of the inventive concept, thereconstruction unit 140 may digitally reconstruct a plurality ofholograms corresponding to the respective wavelengths to generate imagesof a plurality of inspection objects 200. In addition, thereconstruction unit 140 may digitally reconstruct a plurality ofholograms corresponding to the respective wavelengths to generate onecomposite image of the inspection object 200. The reconstruction unit140 may combine a plurality of holograms and generate a composite imagebased on the combined holograms. For example, the reconstruction unit140 may combine a plurality of holograms by averaging information of theplurality of holograms, or may combine a plurality of holograms byweighting hologram information according to wavelengths.

In the DHM 100 a according to embodiments of the inventive concept, aplurality of holograms are generated by using the light source 110 a,which is a multi-wavelength light source, and the spectrometer 115, andthe reconstruction unit 140 generates a composite image of theinspection object 200 based on a plurality of holograms, and thus, theresolution of an image of the inspection object 200 may be greatlyimproved. In other words, a hologram corresponding to each wavelengthand an image of the inspection object 200 corresponding to the hologrammay have a somewhat lower resolution due to the absence of a lens. Onthe other hand, the combination of a plurality of holograms and acomposite image of the inspection object 200 corresponding thereto mayhave a high resolution in spite of the absence of a lens.

FIGS. 3A and 3B are conceptual diagrams of a DHM 100 b according to anembodiment of the inventive concept. Descriptions already given withreference to FIGS. 1A to 2D will be briefly described or omitted.

Referring to FIGS. 3A and 3B, the DHM 100 b according to embodiments ofthe inventive concept may be different from the DHM 100 of FIG. 1A inthat an inspection object 200 is moved in one direction by the movementof a stage 160. Specifically, in the DHM 100 b according to embodimentsof the inventive concept, the stage 160 may be moved in a firstdirection (i.e., the x direction), as indicated by a black arrow M1, andaccordingly, the inspection object 200 may be moved in the firstdirection (i.e., the x direction). The first direction (i.e., the xdirection) may be a direction parallel to the upper surface of theinspection object 200. In the DHM 100 b according to embodiments of theinventive concept, due to the movement of the inspection object 200, adetector 130 may generate a plurality of holograms and thereconstruction unit 140 may generate a composite image of the inspectionobject 200 based on the plurality of holograms. Accordingly, similar tothe DHM 100 a of FIG. 2A, the DHM 100 b according to embodiments of theinventive concept may improve the resolution of an image of theinspection object 200.

For example, a first hologram may be generated by light from a lightsource 110 when the inspection object 200 is at a first position P0.Thereafter, the inspection object 200 may move to a second position P2by the movement of the stage 160 in the first direction (i.e., the xdirection) and a second hologram may be generated by light from thelight source 110.

The principle that another hologram is formed according to the movementof the inspection object 200 may be described as follows by using theprinciple of the formation of a two-dimensional image. As shown in FIG.3B, the detector 130 may include a pixel 132 in which an imagecorresponding to a defect De is formed, and a cover glass 134 coveringthe pixel 132. The position of the pixel 132 in which the imagecorresponding to the defect De is formed may be changed by the movementof the inspection object 200. In other words, the movement of theinspection object 200 may correspond to the movement of the detector 130in a second direction (i.e., the y direction), and the second direction(i.e., the y direction) may be a direction parallel to a pixel surfaceof the detector 130.

For example, when the inspection object 200 is at the first position P0,an image corresponding to the defect De may be formed over two pixels132, and when the inspection object 200 is at the second position P1, animage corresponding to the defect De may be formed in one pixel 132.Accordingly, in the case of the first position P0, the intensityinformation of light for the defect De may be stored by two pixels 132,and in the case of the second position P1, the intensity information oflight for the defect De may be stored by one pixel 132. Generally, theintensity information of light by two pixels 132 may be more accuratethan the intensity information of light by one pixel 132. However, theremay be an opposite case due to noise at a pixel boundary. Similar to atwo-dimensional image of the defect De, the intensity and phaseinformation of light in a hologram that is a three-dimensional image ofthe defect De may also be changed according to the position of theinspection object 200.

FIGS. 4 to 8 are conceptual diagrams of DHMs 100 c to 100 g according toembodiments of the inventive concept. Descriptions already given withreference to FIGS. 1A to 3B will be briefly described or omitted.

Referring to FIG. 4, the DHM 100 c may be similar, in principle, to theDHM 100 b of FIG. 3A. Specifically, in the DHM 100 b of FIG. 3A, theinspection object 200 moves by the movement of the stage 160. However,in the DHM 100 c according to embodiments of the inventive concept, adetector 130 may move in a second direction (i.e., the y direction), asindicated by a black arrow M2. The second direction (i.e., the ydirection) may be a direction parallel to the surface of a pixel in thedetector 130.

Also in the DHM 100 c, the detector 130 generates a plurality ofholograms based on the movement of the detector 130, and accordingly areconstruction unit 140 generates a composite image of an inspectionobject 200, and thus, the resolution of an image of the inspectionobject 200 may be improved.

Referring to FIG. 5, the DHM 100 d may be in a form obtained bycombining the DHM 100 a of FIG. 2A with the DHM 100 b of FIG. 3A or theDHM 100 c of FIG. 4A. Specifically, the DHM 100 d includes a lightsource 110 a, which is a multi-wavelength light source, and aspectrometer 115. In the DHM 100 d, an inspection object 200 may move ina first direction (i.e., the x direction) by a stage 160, or a detector130 may move in a second direction (i.e., the y direction).

In the DHM 100 d, a plurality of first holograms according towavelengths may be formed, and a plurality of second holograms may beformed by the movement of the inspection object 200 or the movement ofthe detector 130. A reconstruction unit 140 may generate a compositeimage of the inspection object 200 based on the plurality of firstholograms and the plurality of second holograms. Thus, the DHM 100 d mayfurther improve the resolution of an image of the inspection object 200.

Referring to FIGS. 6A and 6B, the DHM 100 e may be different from theDHM 100 b of FIG. 3A or the DHM 100 c of FIG. 4 in that the DHM 100 emakes light from a light source 110 incident on an inspection object 200at different angles. However, the DHM 100 e may be substantially thesame as the DHM 100 b of FIG. 3A or the DHM 100 c of FIG. 4 in terms ofeffects.

In the DHMs 100 and 100 a to 100 d of FIGS. 1A to 5, light from thelight sources 110 and 110 a may be vertically incident on the uppersurface of the inspection object 200. On the other hand, in the DHM 100e, light from the light source 110 may be incident on the upper surfaceof the inspection object 200 while changing an angle in a first anglerange R_(θ1). For example, the maximum angle of the first angle rangeR_(θ1) may have a first angle θ1 with respect to a normal line of theupper surface of the inspection object 200. The first angle θ1 may be 1°or less. However, the first angle θ1 is not limited thereto.

As the light from the light source 110 is incident on the upper surfaceof the inspection object 200 with different angles, the detector 130 maygenerate a plurality of holograms corresponding to incidence angles. Theprinciple that different holograms are generated as the light from thelight source 110 is incident on the upper surface of the inspectionobject 200 at different incidence angles may be similar to thatdescribed in the description of the DHM 100 b of FIG. 3A.

Specifically, when an incidence angle of light that is incident on theupper surface of the inspection object 200 is changed, an angle at whichreflected light from the inspection object 200 is incident on thedetector 130 may be changed. For example, as shown in FIG. 6B, whenreflected light for a defect De located at the same position is incidenton the detector 130, the position of a pixel 132 in which an image ofthe defect De is formed may be changed according to an incidence angleof the reflected light. Thus, a case where an incidence angle of lightis changed on the upper surface of the inspection object 200 hassubstantially the same effect as a case where the inspection object 200moves in the DHM 100 b of FIG. 3A or the detector 130 moves in the DHM100 c of FIG. 4.

FIG. 6B shows the structure of the detector 130 in an exaggeratedmanner. In general, the sizes of pixels in the detector 130 are fine asabout 1 μm, but the thickness of a cover glass 134 may be very large asseveral hundreds of μm. Thus, the position of the pixel 132 in which theimage of the defect De is formed may be greatly changed even with aslight change in the incidence angle of light. In consideration of thispoint, as described above, the first angle range R_(θ1) of light on theupper surface of the inspection object 200 may be set very finely.

In the DHM 100 e, the detector 130 may generate a plurality of hologramsby changing an incidence angle of light on the upper surface of theinspection object 200, and the reconstruction unit 140 may generate acomposite image of the inspection object 200 based on the plurality ofholograms. Thus, the DHM 100 e may improve the resolution of an image ofthe inspection object 200.

Referring to FIG. 7, the DHM 100 f may be similar, in principle, to theDHM 100 e of FIG. 6A. Specifically, in the DHM 100 e of FIG. 6A, anangle of incidence of light of the light source 110 onto the inspectionobject 200 is changed. However, in the DHM 100 f, a detector 130 mayrotate in a second angle range R_(θ2) such that an angle of incidence ofreflected light onto a pixel surface of the detector 130 changes. Forexample, the maximum angle of the second angle range R_(θ2) may have asecond angle θ2 with respect to the pixel surface of the detector 130before rotation. The second angle θ2 may also be as small as 1° or less.However, the second angle θ2 is not limited thereto. The second anglerange R_(θ2) may correspond to a change range of an incidence angle ofreflected light to a normal line of the pixel surface.

The DHM 100 f may have the same effect as the DHM 100 e of FIG. 6Abecause the detector 130 in the DHM 100 f rotates in the second anglerange R_(θ2) and an angle of incidence of reflected light onto the pixelsurface of the detector 130 changes. Thus, the DHM 100 f also mayimprove the resolution of an image of the inspection object 200 bygenerating a plurality of holograms by rotation of the detector 130 andgenerating a composite image of the inspection object 200.

Referring to FIG. 8, the DHM 100 g may be in a form obtained bycombining the DHM 100 a of FIG. 2A with the DHM 100 e of FIG. 6A or theDHM 100 f of FIG. 7. Specifically, the DHM 100 g includes a light source110 a, which is a multi-wavelength light source, and a spectrometer 115.In the DHM 100 g, light from the spectrometer 115 may be incident on theupper surface of an inspection object 200 while an incidence angle ofthe light from the spectrometer 115 is changed in a first angle rangeR_(θ1), or reflected light may be incident on the detector 130 while thedetector 130 is rotated in a second angle range R_(θ2).

In the DHM 100 g, a plurality of first holograms according towavelengths may be formed, and a plurality of third holograms may beformed as an incidence angle of light from the spectrometer 115 ischanged in the first angle range R_(θ1) or the detector 130 is rotatedin the second angle range R_(θ2). A reconstruction unit 140 may generatea composite image of the inspection object 200 based on the plurality offirst holograms and the plurality of third holograms. Thus, the DHM 100g may further improve the resolution of an image of the inspectionobject 200.

FIG. 9A is a block diagram of a DHM 100 h according to an embodiment ofthe inventive concept of the inventive concept, and FIG. 9B is aconceptual diagram of the DHM 100 h according to embodiments of theinventive concept. Descriptions already given with reference to FIGS. 1Aand 1B will be briefly described or omitted.

Referring to FIGS. 9A and 9B, the DHM 100 h according to embodiments ofthe inventive concept may be structurally different from the DHMs 100and 100 a to 100 g of FIGS. 1A to 8. Specifically, the DHM 100 haccording to embodiments of the inventive concept may include only alight source 110, a detector 130, a reconstruction unit 140, and ananalysis and determination unit 150, and may not include a beamsplitter.

In the DHM 100 h, light from the light source 110 may be obliquelyincident on an inspection object 200, as shown in FIG. 9B, in order toseparate reflected light from the inspection object 200 from lightincident from the light source 110 onto the inspection object 200because no beam splitter is present. Accordingly, light from the lightsource 110 may be incident with a first incidence angle θi with respectto a normal line of the upper surface of the inspection object 200, andreflected light from the inspection object 200 may be reflected with afirst reflection angle θr with respect to the normal line. According toSnell's law, the first reflection angle θr may be the same as the firstincidence angle θi.

The detector 130 may be arranged at a position where reflected light maybe detected. For example, the detector 130 may be arranged such thatreflected light is incident perpendicularly to a pixel surface of thedetector 130. Accordingly, the pixel surface of the detector 130 mayhave a certain angle with respect to a second direction (i.e., the ydirection). When there is a beam splitter, the direction of reflectedlight may be adjusted by controlling the beam splitter, and thus, thedegree of freedom of an arrangement angle of the detector 130 mayincrease and the detector 130 may be arranged regardless of thestructure or size of the inspection object 200 or the stage 160. On theother hand, in the absence of a beam splitter, when an incidence angleof light that is incident on the inspection object 200 from the lightsource 110 is determined, the degree of freedom of the arrangement angleof the detector 130 may decrease because the arrangement angle of thedetector 130 is determined to some extent, and the position of thedetector 130 may be limited depending on the structure or size of theinspection object 200 or the stage 160. For example, as the detector 130is placed closer to the inspection object 200, reflected light having ahigher intensity may be detected. However, there may be a limit onplacing the detector 130 close to the inspection object 200 according tothe structures and sizes of the inspection object 200 and the stage 160.

The principle that the DHM 100 h according to embodiments of theinventive concept forms a hologram is not so different from theprinciple that the DHM 100 of FIG. 1A forms a hologram. For example,light incident from the light source 110 onto a portion where there is adefect De may be diffracted and reflected and be incident on thedetector 130 as a first reflected light R1. Light incident from thelight source 110 onto a portion where no defect De is present may bereflected without diffraction and be incident on the detector 130 as asecond reflected light R2. The first reflected light R1 and the secondreflected light R2 may overlap each other in the detector 130 to causeinterference. Light caused by the interference, that is, interferencelight may generate a hologram in a pixel of the detector 130. When nodefect De is present in the inspection object 200, the first reflectedlight R1 may not be present and only the second reflected light R2 maybe present. Accordingly, only the second reflected light R2 may beincident on the detector 130 and interference may not occur.

The DHM 100 h according to embodiments of the inventive concept maycorrespond to an optics-free DHM since no beam splitter is present.Accordingly, the DHM 100 h according to embodiments of the inventiveconcept may be realized at a low cost with a simple structure, whilehaving substantially the same effect as the lens less DHMs according tothe embodiments described above.

FIGS. 10 to 13 are conceptual diagrams of DHMs 100 i to 100 l accordingto embodiments of the inventive concept. Descriptions already given withreference to FIGS. 1 to 9B will be briefly described or omitted.

Referring to FIG. 10, the DHM 100 i may be different from the DHM 100 aof FIG. 2A in that the DHM 100 i does not have a beam splitter. Inaddition, the DHM 100 i may be different from the DHM 100 h of FIG. 9Ain that light from a spectrometer 115 of the DHM 100 i is obliquelyincident on an inspection object 200. Specifically, the DHM 100 iincludes a light source 110 a, which is a multi-wavelength light source,and the spectrometer 115, and light from the spectrometer 115 may bedirectly incident, with a first incidence angle θi, on the inspectionobject 200 without passing through a beam splitter.

In the DHM 100 i, a detector 130 may form a plurality of hologramsaccording to wavelengths, as in the DHM 100 a of FIG. 2A, and areconstruction unit 140 may generate a composite image of the inspectionobject 200 based on the plurality of holograms. Thus, the DHM 100 i mayimprove the resolution of an image of the inspection object 200.

Referring to FIG. 11, the DHM 100 j may be in a form obtained bycombining the DHM 100 h of FIG. 9A with the DHM 100 b of FIG. 3A or theDHM 100 c of FIG. 4A. Specifically, in the DHM 100 j, light from a lightsource 110 may be directly incident on an inspection object 200, with afirst incident angle θi, without using a beam splitter, the inspectionobject 200 may move in a first direction (i.e., the x direction) by astage 160, or a detector 130 may move in a second direction (i.e., the ydirection).

In the DHM 100 j, the detector 130 may form a plurality of holograms bythe movement of the inspection object 200 or the movement of thedetector 130. A reconstruction unit 140 may generate a composite imageof the inspection object 200 based on the plurality of holograms. Thus,the DHM 100 j may improve the resolution of an image of the inspectionobject 200.

Referring to FIG. 12, the DHM 100 k may be in a form obtained bycombining the DHM 100 h of FIG. 9A with the DHM 100 e of FIG. 6A or theDHM 100 f of FIG. 7. Specifically, in the DHM 100 k, light from a lightsource 110 may be directly incident on an inspection object 200, with afirst incident angle θi, without using a beam splitter, light from alight source 110 may be obliquely incident on the upper surface of theinspection object 200 while being changed in a third angle range R_(θ3),or reflective light may be incident on a detector 130 while the detector130 rotates in a fourth angle range R_(θ4). The third angle range R_(θ3)may be based on the first incident angle θi, and the maximum angle ofthe third angle range R_(θ3) may have a third angle θ3 and may be lessthan or equal to 1°. The fourth angle range R_(θ4) may be based on apixel surface of the detector 130 before rotation, and the maximum angleof the fourth angle range R_(θ4) may have a fourth angle θ4 and may beless than or equal to 1°.

In the DHM 100 k, as light from the light source 110 is changed in thethird angle range R_(θ3) based on the first incident angle θi or thedetector 130 rotates in a fourth angle range R_(θ4), the detector 130may form a plurality of holograms. A reconstruction unit 140 maygenerate a composite image of the inspection object 200 based on theplurality of holograms. Thus, the DHM 100 k may improve the resolutionof an image of the inspection object 200.

Although not shown in diagrams, a DHM in which the DHM 100 i of FIG. 10and the DHM 100 j of FIG. 11 are combined with each other may also berealized. In such a DHM, a multi-wavelength light source may be used asa light source, a spectrometer may be further included, and aninspection object may be moved by a stage or a detector may be moved.Also, a DHM in which the DHM 100 i of FIG. 10 and the DHM 100 k of FIG.12 are combined with each other may be realized. In such a DHM, amulti-wavelength light source may be used as a light source, aspectrometer may be further included, and light from a light source maybe obliquely incident on an inspection object while being changed in thethird angle range R_(θ3) or reflected light may be incident on adetector while the detector rotates in the fourth angle range R_(θ4).

In a DHM in which the DHM 100 i of FIG. 10 and the DHM 100 j of FIG. 11are combined with each other, a plurality of first holograms accordingto wavelengths may be formed and a plurality of second holograms may beformed due to the movement of an inspection object or the movement of adetector. In a DHM in which the DHM 100 i of FIG. 10 and the DHM 100 kof FIG. 12, a plurality of first holograms corresponding to wavelengthsmay be formed and a plurality of third holograms may be formed as lightfrom a light source is changed in the third angle range R_(θ3) or adetector rotates in the fourth angle range R_(θ4). Accordingly, areconstruction unit may generate a composite image of an inspectionobject based on the plurality of first holograms and the plurality ofsecond holograms, or the plurality of first holograms and the pluralityof third holograms, thereby improving the resolution of an image of theinspection object.

Referring to FIG. 13, the DHM 100 l may be substantially the same as theDHM 100 of FIG. 1A. However, the DHM 100 l may not detect a defect in aninspection object 200 but measure the structure of a pattern Pt formedon the inspection object 200. In addition, the DHM 100 l may determinewhether the inspection object 200 is defective by analyzing whether ameasured structure of the pattern Pt matches a required structure.

The principle of measuring the structure of the pattern Pt may besubstantially the same as the principle of finding a defect. Forexample, the detector 130 may generate a hologram based on interferencebetween light diffracted and reflected at a portion of the inspectionobject 200 where a pattern is formed and light reflected at a portion ofthe inspection object 200 where a pattern is not formed, and areconstruction unit (see the reconstruction unit 140 in FIG. 1A) maydigitally reconstruct the hologram to generate an image of theinspection object 200, for example, an image of the pattern of theinspection object 200. Then, an analysis and determination unit (see theanalysis and determination unit 150 in FIG. 1A) may compare an image ofthe structure of the pattern with a reference pattern structure tothereby determine whether the inspection object 200 is defective or not.

Although not shown in drawings, the DHMs 100 a to 100 k having variousstructures shown in FIGS. 3A to 12 may also be used for measuring thestructure of the pattern Pt formed on the inspection object 200.

FIG. 14 is a flowchart of an inspection method using a DHM according toan embodiment of the inventive concept. The inspection method will bedescribed with reference to FIGS. 1A to 13, and descriptions alreadygiven with reference to FIGS. 1A to 13 will be briefly described oromitted.

Referring to FIG. 14, first, light is generated by the light source 110and is incident on the inspection object 200 (operation S110). The lightgenerated by the light source 110 may be monochromatic light ormulti-wavelength light. Various embodiments related to the incidence oflight onto the inspection object 200 will be described in more detailwith reference to FIGS. 15A to 15D.

Next, the detector 130 detects reflected light reflected from theinspection object 200 (operation S130). The reflected light may includediffracted and reflected light, that is, the first reflected light R1,and light reflected without diffraction, that is, the second reflectedlight R2. The reflected light may include only the second reflectedlight R2.

It is determined whether the reflected light includes interference light(operation S140). That is, it is determined whether the reflected lightis interference light caused by an overlap between the first reflectedlight R1 and the second reflected light R2 or is the second reflectedlight R2. The interference light may be formed as the first reflectedlight R1 and the second reflected light R2 overlap each other in thebeam splitter 120 or the detector 130.

If it is determined that the reflected light includes interference light(Yes), the detector 130 generates a hologram based on the interferencelight (operation S150). According to an embodiment of the inventiveconcept, the detector 130 may generate a plurality of holograms for eachwavelength, for each position of the inspection object 200, for eachposition of the detector 130, for each angle of incidence of light ontothe inspection object 200, or for each angle of incidence of reflectedlight onto the detector 130.

The reconstruction unit 140 generates an image of the inspection object200 based on a hologram generated by the detector 130 (operation S170).When the detector 130 generates a plurality of holograms, thereconstruction unit 140 may generate a composite image of the inspectionobject 200 based on the plurality of holograms.

The analysis and determination unit 150 analyzes the reflected light,the hologram, or the image to determine whether there is a defect in theinspection object 200 (operation S190). More specifically, when thedetector 130 generates a hologram, the reconstruction unit 140 maygenerate an image of the inspection object 200 based on the hologram.Accordingly, the analysis and determination unit 150 may analyze theimage from the reconstruction unit 140 and determine whether there is adefect in the inspection object 200.

According to an embodiment of the inventive concept, the reconstructionunit 140 may be omitted, and operation S170 of generating an image ofthe inspection object may be omitted. In this case, the analysis anddetermination unit 150 may analyze the hologram generated by thedetector 130 and determine whether there is a defect in the inspectionobject 200.

If it is determined that the reflected light does not includeinterference light (No), the analysis and determination unit 150analyzes the reflected light incident on the detector 130 and determineswhether there is a defect in the inspection object 200 (operation S190).For example, when no defect is present in the inspection object 200 andthere is only the second reflected light R2, interference light may notbe generated. Thus, the reflected light may not include interferencelight, and the detector 130 may not generate a hologram. In this manner,when the detector 130 may not generate a hologram, the analysis anddetermination unit 150 may directly analyze reflected light incident onthe detector 130 to determine whether a defect is present in theinspection object 200.

According to an embodiment of the inventive concept, when the detector130 may not generate a hologram, the reconstruction unit 140 may use animage generated by reflected light incident on the detector 130 as animage of the inspection object 200. In this case, the analysis anddetermination unit 150 may analyze the image of the inspection object200 to determine whether a defect is present in the inspection object200.

FIGS. 15A to 15D are flowcharts illustrating in more detail variousembodiments of operation S110 a of making light incident on aninspection object, in the inspection method of FIG. 14. The variousembodiments will be described with reference to FIGS. 1A to 13 and FIGS.15A to 15D. Descriptions already given with reference to FIGS. 1A to 14will be briefly described or omitted.

Referring to FIG. 15A, operation S110 a of making light incident on aninspection object, according to an embodiment of the inventive concept,is as follows. First, light is generated by the light source 110 and isincident on the beam splitter 120 (operation S112). The light generatedby the light source 110 may be monochromatic light.

The beam splitter 120 causes the light from the light source 110 to beincident on the inspection object 200 and outputs reflected light fromthe inspection object 200 (operation S114). The beam splitter 120 maytransmit or reflect the light from the light source 110 to be incidenton the inspection object 200 and may reflect or transmit reflected lightfrom the inspection object 200 to be output. The reflected light outputfrom the beam splitter 120 may be interference light due to an overlapbetween the first reflected light R1 and the second reflected light R2.The interference light output from the beam splitter 120 may be detectedby the detector 130, and thus, a hologram may be generated by thedetector 130.

Referring to FIG. 15B, operation S110 b of making light incident on aninspection object, according to an embodiment of the inventive concept,is as follows. First, light is generated by the light source 110 a andis incident on the spectrometer 115 (operation S111). The lightgenerated by the light source 110 a may be multi-wavelength light.

The spectrometer 115 separates multi-wavelength light from the lightsource 110 a by wavelengths (operation S113). Light separated for eachwavelength may be output for each wavelength through the slit plate 117.

The light separated for each wavelength through the spectrometer 115 isincident on the inspection object 200, and reflected light is outputfrom the inspection object 200 (operation S115). The reflected lightfrom the inspection object 200 may be detected by the detector 130. Inthis case, by controlling the slit plate 117 and making light having arequired wavelength incident on the inspection object 200, reflectedlight may be detected by the detector 130 for each wavelength. Inaddition, each of reflected lights according to wavelengths may beinterference light caused by an overlap between the first reflectedlight R1 and the second reflected light R2. Accordingly, the detector130 may generate a plurality of holograms corresponding to a pluralityof interference lights.

Referring to FIG. 15C, operation S110 c of making light incident on aninspection object, according to an embodiment of the inventive concept,is as follows. First, light is generated by the light source 110 a andis incident on the spectrometer 115 (operation S111). The lightgenerated by the light source 110 a may be multi-wavelength light.

The spectrometer 115 separates multi-wavelength light from the lightsource 110 a by wavelengths (operation S113). Light separated for eachwavelength may be output for each wavelength through the slit plate 117.

The light separated for each wavelength by the spectrometer 115 isincident on the beam splitter 120 (operation S112 a).

The beam splitter 120 causes the light separated for each wavelength tobe incident on the inspection object 200 and outputs reflected lightfrom the inspection object 200 (operation S114). The beam splitter 120may transmit or reflect the light separated for each wavelength to beincident on the inspection object 200 and may reflect or transmitreflected light from the inspection object 200 to be output.

By controlling the slit plate 117 and making light having a requiredwavelength incident on the beam splitter 120 to make the light incidenton the inspection object 200, reflected light may be output from thebeam splitter 120 for each wavelength. Each of reflected lights outputfrom the beam splitter 120 may be interference light caused by anoverlap between the first reflected light R1 and the second reflectedlight R2. Accordingly, the detector 130 may generate a plurality ofholograms corresponding to the plurality of interference lights.

Referring to FIG. 15D, light is generated by the light source 110 and isobliquely incident on the upper surface of the inspection object 200,and reflected light is output from the inspection object 200 (operationS110 d). The output reflected light may be interference light due to anoverlap between the first reflected light R1 and the second reflectedlight R2 and may be detected by the detector 130. Thus, the detector 130may generate a hologram corresponding to the interference light.

FIG. 16 is a flowchart of a method of manufacturing a semiconductordevice by using a DHM, according to an embodiment of the inventiveconcept. The method will be described with reference to FIGS. 1A to 13and FIG. 16. Descriptions already given with reference to FIGS. 1A to 15d will be briefly described or omitted.

Referring to FIG. 16, operation S110 of generating light and making thelight incident on the inspection object 200 to operation S190 ofanalyzing reflected light, a hologram, or an image and determiningwhether a defect is present are performed. Descriptions of operationsS110 to S190 in FIG. 16 are as described above with reference to FIGS.14 to 15D.

Operation S190 may include operation S192 of analyzing reflected light,a hologram, or an image and operation S195 of determining whether adefect is present.

If it is determined, in operation S195, that no defect is present (No),a semiconductor process is performed on the inspection object 200(operation S210). For example, when the inspection object 200 is awafer, a semiconductor process may be performed on the wafer. Thesemiconductor process for the wafer may include various processes. Forexample, the semiconductor process for the wafer may include adeposition process, an etching process, an ion implantation process, acleaning process, and the like. Integrated circuits and wirings requiredfor the semiconductor device may be faulted by performing thesemiconductor process for the wafer. The semiconductor process for thewafer may include a process of testing the semiconductor device at awafer level.

When semiconductor chips in the wafer are completed through thesemiconductor process for the wafer, the wafer may be divided into thesemiconductor chips. Divisions into the semiconductor chips may beachieved through a sawing process by a blade or a laser. Thereafter, apackaging process may be performed on the semiconductor chips. Thepackaging process may refer to a process in which the semiconductorchips are mounted on a printed circuit board (PCB) and sealed with asealing material. The packaging process may include stacking a pluralityof semiconductor chips on a PCB to form a stack package, or stacking astack package on another stack package to form a package on package(POP) structure. A semiconductor device or a semiconductor package maybe completed through a packaging process for a semiconductor chip. Atest process may be performed on the semiconductor package after thepackaging process.

If it is determined, in operation S195, that a defect is present (Yes),the type and cause of the defect are analyzed (operation S220).According to an embodiment of the inventive concept, a process ofremoving the defect through cleaning or the like or of discarding theinspection object 200 may be performed depending on the type of thedefect.

While the inventive concept has been particularly shown and describedwith reference to embodiments thereof, it will be understood thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the following claims.

What is claimed is:
 1. A digital holography microscope (DHM) comprising:a light source configured to generate and output light; a beam splitterconfigured to permit the light to be incident on an inspection objectand output reflected light from the inspection object; and a detectorconfigured to detect the reflected light, wherein the detector generatesa hologram when the reflected light comprises interference light,wherein the light source, the beam splitter, and the detector arearranged such that when a defect is present on the inspection object,light diffracted and reflected at a portion of the inspection objectwhere a defect is present and light reflected and not diffracted at aportion of the inspection object where no defect is present overlap eachother, thus generating the interference light, and wherein the DHM has alens-free path from the light source to the detector.
 2. The DHM ofclaim 1, wherein the detector does not generate a hologram when theinspection object has no defects.
 3. The DHM of claim 1, wherein thelight source comprises a multi-wavelength light source, the detector isconfigured to generate a hologram for each wavelength, and the DHMfurther comprises a spectrometer configured to separate the light bywavelengths.
 4. The DHM of claim 1, wherein the inspection object isconfigured to be moved in a horizontal direction with respect to anupper surface of the inspection object, and wherein the detector isconfigured to generate a hologram for each position of the inspectionobject in the horizontal direction.
 5. The DHM of claim 1, wherein thedetector is configured to be moved in a horizontal direction withrespect to a pixel surface of the detector, and wherein the detector isconfigured to generate a hologram for each position of the detector inthe horizontal direction.
 6. The DHM of claim 1, configured such thatthe light is incident while an angle of the light source is changedwithin a range set with respect to a normal line of an upper surface ofthe inspection object, and wherein the detector is configured togenerate a hologram for each angle of incidence of the light onto theinspection object.
 7. The DHM of claim 1, configured such that thereflected light is incident while an angle of the detector is changedwithin a range set with respect to a normal line of a pixel surface ofthe detector, and wherein the detector is configured to generate ahologram for each angle of incidence of the reflected light onto thedetector.
 8. The DHM of claim 1, further comprising: a reconstructionunit configured to digitally reconstruct the hologram to generate animage of the inspection object; and an analysis and determination unitconfigured to analyze the reflected light, the hologram, or the image todetermine whether a defect is present in the inspection object.
 9. TheDHM of claim 8, wherein, when a plurality of holograms is generateddepending on light wavelength, a position of the inspection object, aposition of the detector, an angle of incidence of light onto theinspection object, or an angle of incidence of reflected light onto thedetector, the reconstruction unit generates a composite image of theinspection object based on the plurality of holograms.
 10. A digitalholography microscope (DHM) comprising: a light source configured togenerate and output light; a detector configured to detect reflectedlight produced when the light is vertically incident on an upper surfaceof an inspection object or incident at a set inclination angle; and ananalysis and determination unit configured to analyze the reflectedlight to determine whether a defect is present in the inspection object,wherein the detector generates a hologram when the reflected lightcomprises interference light and the analysis and determination unitanalyzes the hologram, wherein the reflected light includes reflectedand diffracted light, and reflected and non-diffracted light, whichinterfere with each other to result in the interference light, andwherein a first light formed by the generated and output light and thereflected and diffracted light and a second light formed by thegenerated and output light and the reflected and non-diffracted lightfollow the same path between the light source and the detector, andwherein the DHM has a lens-free path from the light source to thedetector.
 11. The DHM of claim 10, wherein the light source and thedetector are arranged such that the reflected and diffracted light islight diffracted and reflected at a portion of the inspection objectwhere there is the defect and the reflected and non-diffracted light islight reflected at a portion of the inspection object where there is nodefect, so that the interference light is generated when a defect ispresent in the inspection object.
 12. The DHM of claim 10, furthercomprising: a beam splitter, wherein the generated and output light isvertically incident on the upper surface of the inspection object, andthe beam splitter permits the light to be incident on the inspectionobject and outputs the reflected light to the detector.
 13. The DHM ofclaim 10, wherein the light source comprises a multi-wavelength lightsource, the detector is configured to generate a hologram for eachwavelength, and the DHM further comprises a spectrometer configured toseparate the generated and output light by wavelengths.
 14. The DHM ofclaim 10, wherein the inspection object is configured to be moved in ahorizontal direction with respect to an upper surface of the inspectionobject, or the detector is configured to be moved in a horizontaldirection with respect to a pixel surface of the detector, and whereinthe detector is configured to generate a hologram for each position ofthe inspection object in the horizontal direction or for each positionof the detector in the horizontal direction.
 15. The DHM of claim 10,configured such that the generated and output light is incident while anangle of the light source is changed within a range set with respect tothe inclination angle, or the reflected light is incident while an angleis changed within a range set with respect to a normal line of a pixelsurface of the detector, and wherein the detector is configured togenerate a hologram for each angle of incidence of the light onto theinspection object or for each angle of incidence of the reflected lightonto the detector.
 16. The DHM of claim 10, further comprising: areconstruction unit configured to digitally reconstruct the hologram togenerate an image of the inspection object, wherein the reconstructionunit generates a composite image of the inspection object based on aplurality of holograms and the analysis and determination unit analyzesthe image or the composite image when the plurality of holograms isgenerated depending on light wavelength, a position of the inspectionobject, a position of the detector, an angle of incidence of light ontothe inspection object or an angle of incidence of reflected light ontothe detector.
 17. A digital holography microscope (DHM) comprising: alight source configured to generate and output light; a beam splitterconfigured to permit the light to be incident on an inspection objectand output reflected light from the inspection object; and a detectorconfigured to detect the reflected light, wherein the detector generatesa hologram when the reflected light comprises interference light, thehologram generated using the interference light, and wherein theinterference light is formed from interference between a reference beamreflected and not diffracted off of a portion of the inspection objectthat includes a defect, and an object beam that is both reflected anddiffracted by a portion of the inspection object, and both the referencebeam and object beam follow the same path between the inspection objectand the detector.
 18. The DHM of claim 17, wherein the detector does notgenerate a hologram when the inspection object has no defects.
 19. TheDHM of claim 17, wherein the DHM has no lenses between the light sourceand the detector.